On Fri, May 24, 2024 at 9:31 AM Richard Biener <rguent...@suse.de> wrote: > > On Wed, 22 May 2024, Manolis Tsamis wrote: > > > The match.pd patterns to merge two vector permutes into one fail when a > > potentially no-op view convert expressions is between the two permutes. > > This change lifts this restriction. > > > > gcc/ChangeLog: > > > > * match.pd: Allow no-op view_convert between permutes. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.dg/fold-perm-2.c: New test. > > > > Signed-off-by: Manolis Tsamis <manolis.tsa...@vrull.eu> > > --- > > > > gcc/match.pd | 14 ++++++++------ > > gcc/testsuite/gcc.dg/fold-perm-2.c | 16 ++++++++++++++++ > > 2 files changed, 24 insertions(+), 6 deletions(-) > > create mode 100644 gcc/testsuite/gcc.dg/fold-perm-2.c > > > > diff --git a/gcc/match.pd b/gcc/match.pd > > index 07e743ae464..cbb3c5d86e0 100644 > > --- a/gcc/match.pd > > +++ b/gcc/match.pd > > @@ -10039,19 +10039,21 @@ and, > > d = VEC_PERM_EXPR <a, b, NEW_VCST>; */ > > > > (simplify > > - (vec_perm (vec_perm@0 @1 @2 VECTOR_CST@3) @0 VECTOR_CST@4) > > + (vec_perm (view_convert?@0 (vec_perm@1 @2 @3 VECTOR_CST@4)) @0 > > VECTOR_CST@5) > > (if (TYPE_VECTOR_SUBPARTS (type).is_constant ()) > > (with > > { > > machine_mode result_mode = TYPE_MODE (type); > > - machine_mode op_mode = TYPE_MODE (TREE_TYPE (@1)); > > + machine_mode op_mode = TYPE_MODE (TREE_TYPE (@2)); > > int nelts = TYPE_VECTOR_SUBPARTS (type).to_constant (); > > vec_perm_builder builder0; > > vec_perm_builder builder1; > > vec_perm_builder builder2 (nelts, nelts, 1); > > } > > - (if (tree_to_vec_perm_builder (&builder0, @3) > > - && tree_to_vec_perm_builder (&builder1, @4)) > > + (if (tree_to_vec_perm_builder (&builder0, @4) > > + && tree_to_vec_perm_builder (&builder1, @5) > > + && element_precision (TREE_TYPE (@0)) > > + == element_precision (TREE_TYPE (@1))) > > I think you want to check TYPE_SIZE (TREE_TYPE (@0/@1)) for equality > instead. >
I think TYPE_SIZE is not enough as we need the vector elements to have the same size, not just the vector as a whole. For example, when using the TYPE_SIZE check instead the following testcase miscompiles typedef int veci __attribute__ ((vector_size (4 * sizeof (int)))); typedef double vecd __attribute__ ((vector_size (2 * sizeof (double)))); void fun (veci *a, veci *b, veci *c) { char data[16]; veci r1 = __builtin_shufflevector (*a, *b, 0, 5, 2, 7); vecd r2; __builtin_memcpy(data, &r1, sizeof(veci)); __builtin_memcpy(&r2, data, sizeof(vecd)); vecd r3 = __builtin_shufflevector (r2, r2, 1, 0); __builtin_memcpy(data, &r3, sizeof(vecd)); __builtin_memcpy(c, data, sizeof(veci)); } To: ldr q31, [x0] rev64 v31.4s, v31.4s str q31, [x2] ret > Otherwise OK. > > Thanks, > Richard. > > > (with > > { > > vec_perm_indices sel0 (builder0, 2, nelts); > > @@ -10073,10 +10075,10 @@ and, > > ? (!can_vec_perm_const_p (result_mode, op_mode, sel0, false) > > || !can_vec_perm_const_p (result_mode, op_mode, sel1, > > false)) > > : !can_vec_perm_const_p (result_mode, op_mode, sel1, false))) > > - op0 = vec_perm_indices_to_tree (TREE_TYPE (@4), sel2); > > + op0 = vec_perm_indices_to_tree (TREE_TYPE (@5), sel2); > > } > > (if (op0) > > - (vec_perm @1 @2 { op0; }))))))) > > + (view_convert (vec_perm @2 @3 { op0; })))))))) > > > > /* Merge > > c = VEC_PERM_EXPR <a, b, VCST0>; > > diff --git a/gcc/testsuite/gcc.dg/fold-perm-2.c > > b/gcc/testsuite/gcc.dg/fold-perm-2.c > > new file mode 100644 > > index 00000000000..1a4ab4065de > > --- /dev/null > > +++ b/gcc/testsuite/gcc.dg/fold-perm-2.c > > @@ -0,0 +1,16 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-O -fdump-tree-fre1" } */ > > + > > +typedef int veci __attribute__ ((vector_size (4 * sizeof (int)))); > > +typedef unsigned int vecu __attribute__ ((vector_size (4 * sizeof > > (unsigned int)))); > > + > > +void fun (veci *a, veci *b, veci *c) > > +{ > > + veci r1 = __builtin_shufflevector (*a, *b, 0, 5, 2, 7); > > + vecu r2 = __builtin_convertvector (r1, vecu); > > + vecu r3 = __builtin_shufflevector (r2, r2, 2, 3, 1, 0); > > + *c = __builtin_convertvector (r3, veci); > > +} > > + > > +/* { dg-final { scan-tree-dump "VEC_PERM_EXPR.*{ 2, 7, 5, 0 }" "fre1" } } > > */ > > +/* { dg-final { scan-tree-dump-times "VEC_PERM_EXPR" 1 "fre1" } } */ > > > > -- > Richard Biener <rguent...@suse.de> > SUSE Software Solutions Germany GmbH, > Frankenstrasse 146, 90461 Nuernberg, Germany; > GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)